1. Field of the Invention
The present invention relates to a method of stabilizing compositions containing surfactants by adding a copolymer to the composition, where the copolymer contains anionic monomer units, cationic monomer units having a side chain containing a surface-active group and, optionally, nonionic monomer units and additional cationic monomer units which do not contain a surface-active group. The copolymer may be used, for example, to stabilize detergent and cosmetic compositions containing surfactants against phase separation.
2. Description of the Background
Modern detergents and cosmetics tend increasingly to contain rheological modifiers and/or anti-tartar agents (in the case of dentifrices and the like), surfactants (anionic, cationic, amphoteric or nonionic), and also, in many cases, "builders" (such as borates, citrates, sodium formate and salts of weak acids), along with, possibly, a variety of other agents (e.g. propylene glycol, optical brighteners, etc.).
Those skilled in the art are therefore confronted with the problem of the compatibility of a rheological modifier (e.g. dispersant or thickener) and/or an anti-tartar agent with the surfactants present in the formulation. Heretofore, lacking a solution to this compatibility problem, those skilled in the art have had to choose dispersants, thickeners or anti-tartar agents based on the surfactant(s) used in the detergent or cosmetic formulation.